Dynamic damping and stiffening system for sliding boards

ABSTRACT

A stiffening or damping apparatus for sliding boards or skis, comprising a force transmission blade ( 20 ) attached to the sliding board ( 10 ) for transmitting vibrational, twisting or bending energy and a clutch element for engaging the force transmission blade. The clutch element ( 26 ) can be constructed to engage in both directions of ski bend over only a portion of total possible movement, or to frictionally engage ( 44 ) in only one direction of ski bending. These clutch devices allows the ski to be damped or stiffened only for small ranges of vibrational movement or to be inhibited in a single direction of bend or torsion.

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] This invention relates to a control apparatus for varying thedamping or stiffness characteristics of a sliding board, snowboard orski according to the nature of the snow, the activity of the user andthe dynamic conditions encountered, to improve the quality of the skiingand safety of the skier.

[0003] 2. Description of Background and Relevant Information

[0004] Modern skis and sliding boards are typically built with amultiplayer composite construction consisting of resilient materials.Skis usually include features for damping the vibrations of the skiresulting from the spring characteristics of the resilient materialsinteracting with the varied and uneven terrain encountered by a skier.An example of ski construction incorporated viscoelastic material isdepicted by Caldwell (U.S. Pat. No. 3,537,717). In other cases, devicesare affixed to skis to dampen vibration as illustrated by (U.S. Pat. No.6,270,108).

[0005] Despite these improvements, difficulties in controlling thevibrations of skis still persist. A ski or sliding board must transitionrapidly and dynamically from the unflexed state utilized in straightrunning to and from the flexed state corresponding to the arc of a turn.The ease of flexing the ski into a turn and the return of energy fromthe bent ski to the skier upon completion of a turn are both impeded bya damping. Therefore damping devices on current skis are tuned toprovide minimal damping so as not to result in a an overdamped or ‘dead’ski as mentioned by Julien (U.S. Pat. No. 6,267,402). Because of thisconstraint on damping forces, ski vibration, chatter and other negativeeffects of insufficient damping persist.

[0006] Insufficient damping in a turn allows the ski edge to bounce orchatter, causing loss of static friction in the established turninggroove or carve. The ski will then dynamically bounce, skid, rebound andregrip into a longer turn radius bend. This causes the skier to losebalance towards the inside of the turn due to the reduced centrifugalforce in the larger radius turn. Damping is also desired during straightahead running to improve stability and ride smoothness.

[0007] Total ski stiffness and ski stiffness distribution also greatlyimpacts the suitability of a ski for different conditions, terrain, andskiing style. Increased ski stiffness increases the skier's control, butcan knock the skier off balance when large bumps in the terrain areencountered. Many skiers buy multiple pairs of skis for differentconditions, for example, soft mogul skis for bumpy terrain and stiffskis for fast speeds and icy terrain. Devices for changing skiflexibility based on the absolute amount of bend in a ski are shown byStepanek et al. (U.S. Pat. No. 5,301,976) and Le Masson (U.S. Pat. No.5,597,170). These devices allow the flex modulus of the ski to changepositively or negatively according to the amount of ski flex, to be moreadaptable to terrain conditions and skiing style. A ski with aconfigurable flex pattern along the length of the ski is shown byChernega (U.S. Pat. No. 4,577,886).

[0008] Another method of selectively engaging damping or biasingelements of a ski is shown by Bonvallet (U.S. Pat. No. 5,806,875). Theskier's weight presses on a clutch element to engage damping. The Comp1400 Piston ski binding currently manufactured by Marker LTD. features ahydraulic piston with differential damping in extension and rebound.

[0009] Even with these improvements, a number of problems exist withexisting ski damping and biasing systems:

[0010] a) Strong damping cannot be applied to the system without causingover damping during the transition between straight running and flexedturn conditions. Thus skiers must continue to contend with chatter andvibration that could be quieted by stronger damping. The skier weightengaged system shown by Bonvallet will engage at the beginning of aturn, restraining the bending of the ski into the flexed turn arc shape,and thus must also have constrained damping to avoid an overdampedcondition during this transition.

[0011] b) Damping cannot be selectively applied to a ski in both of itssteady state conditions of straight running or flexed turn arc. The biassystem shown by Stepanek can engage during a turn, but cannot adaptequally to both small and large radius turns. Le Masson's designfunctions selectively during straight running, but cannot engage dampingor modulus during turning conditions.

[0012] c) Stiffening cannot be increased to increase skier control,without a corresponding increase in upsetting forces applied to theskier by the terrain when larger bumps or transitions are encountered.Stepanek's design provides some relief in this situation, but does notassist the skiers control during a steady state turn by increasing skistiffness during the turn.

[0013] d) Damping engagement cannot be maintained regardless of terrain.When a skier using the Bonvallet design encounters bumps in a turn, theengaging spring force will be released, disengaging damping preciselywhen most needed. The unweighted ski will return to a flat shape faster,causing greater skier loss of balance. The damping in steady state turnconditions should remain engaged to resist ski rebound regardless ofskier loading forces.

[0014] e) Damping or stiffening cannot be selectively applied based onthe current incremental direction of flex of the ski. Suspension systemsfor vehicles employ a damping system where different levels of dampingare applied during compression and rebound. For snowboards and skis in asteady state turn, differential damping or stiffening that stronglyresists extension without impeding maintenance of flexion is desired, toprevent the ski from rebounding into a larger turn radius.

[0015] Marker's piston binding can accomplish directionally differentialdamping, but a piston is inherently a damping device and not ideal fordirectional bias application, if that is the desired result.Additionally, hydraulic pistons are a relatively heavy, large andexpensive way to accomplish selective engagement for a ski application,where the energies to be dissipated are small.

[0016] f) Differential directional damping possibilities for the frontand rear of the ski to maximizing the energy return characteristics of aski are not utilized. A slalom racer utilizes a ski with a soft shoveland stiff tail. The skier leans forward during turn initiation toheavily load the front of the ski and bend the ski into the flexed turnshape as quickly as possible. The skier leans back and pushes off thestiff, bent tail of the ski after the turn is completed to spring offthe tail and accelerate in the direction of the next gate. Heavydirectional rebound damping or biasing in the shovel of the ski could beapplied to stabilize the turn with minimal effect on the racers abilityto accelerate out of the turn. Disengaging damping forces on the tail ofthe ski during transition to and from flexed conditions would maximizeenergy return for the racer.

BRIEF DESCRIPTION OF THE INVENTION

[0017] The invention provides for a clutch mechanism that can engage ordisengage a damping and/or stiffening mechanism for a sliding board. Inone embodiment, the clutch operates in both directions over a limitedrange, and disengages for large excursions in either direction. This canallow a relatively strong damping mechanism to be applied in steadystate straight running and turning conditions, but disengaged for thetransition between states so as not to impede the speed of changingmodes. This clutch mechanism can also allow the resiliency of a ski tobe reduced to better soak up large bumps, with a stiffening member thatengages to increase control during steady state straight running orturning conditions.

[0018] In another embodiment, the clutch operates over only onedirection of bending. This allows the net damping or stiffness of theski to be varied under compression and extension to reduce rebound,without the need for a hydraulic cylinder.

[0019] In both embodiments, the clutch may not lock entirely, but mayallow slippage that allows the ski to move with an added frictionalresistance.

OBJECTS AND ADVANTAGES

[0020] It is an object of the invention to improve the skiers control,balance and grip during varying conditions.

[0021] It is another object of the invention to maximize the efficiencyin which stored energy may be utilized by the skier.

[0022] It is another object of the invention to minimize the negativeeffects during transitions that a damping or stiffening members mayexert on the skier's ability to flex a ski into a turning condition orstraighten a ski for straight running conditions.

[0023] It is another object of the invention to maximize the damping orstiffening force that may be applied to assist the stability of the skiin a steady state turn or straight running condition.

[0024] It is an object of the present invention to provide a clutch forengaging and disengaging a damping member for damping a ski.

[0025] It is another object of the present invention to provide a clutchfor engaging and disengaging a stiffening member for stiffening a ski.

[0026] It is another object of the present invention to provide adamping system for damping a ski, having a damping member which isengageable and disengageable depending upon a skiing condition.

[0027] It is another object of the present invention to provide astiffening system for stiffening a ski, having a stiffening member whichis engageable and disengageable depending upon a skiing condition.

[0028] It is yet another object of the present invention to provide adamping or stiffening system that engages for small vibration inducedchanges in ski shape but that disengages for large changes in ski radiusshape induced by the skier.

[0029] It is yet another object of the present invention to provide astiffening or damping system that can be selectively engaged duringrebound of the ski but disengaged for compression of the ski, or viceversa.

[0030] It is another object of the invention to be able to applydifferent clutch engagement strategies to the front and rear skisegments to maximize skier performance in racing conditions.

[0031] Another object of the invention is to be able to adjust the rangeof motion over which damping or biasing is activated.

[0032] These and other objects will become apparent from the followingdescription of preferred embodiments taken together with theaccompanying drawings and the appended claims.

BRIEF DESCRIPITION OF THE DRAWINGS

[0033] In the drawings, closely related figures have the same number,but different alphabetic suffixes.

[0034] FIGS. 1A-D show a stiffening device on a ski, and close up sideviews of two different clutches, and an end view of a clutch.

[0035] FIGS. 2A-F show prior art concerning selectively engageablestiffening or dampening devices and the force versus displacement graphsassociated with them. The later figures show the configurations andforce versus displacement graphs for the present invention.

[0036] FIGS. 3A-D show operational engagement of a two way clutch over alimited range.

[0037] FIGS. 4A-F show alternate embodiments of two way clutches.

[0038] FIGS. 5A-D show alternate embodiments of single directionclutches.

[0039] FIGS. 6A-E show alternate configuration of clutched damping andstiffening devices, including use of such devices in a binding mountingplatform or binding system.

[0040] FIGS. 7A-C show methods for altering the range of motion overwhich a clutch operates or the strength of the engagement force.

REFERENCE NUMERALS IN DRAWINGS

[0041]10 sliding board 50 eccentric

[0042]12 toe binding 52 axel

[0043]14 heel binding 54 resilient material

[0044]16 damping member 56 friction collar

[0045]18 stiffening member 58 friction collar tunnel

[0046]20 force transmission blade 60 viscoelastic damping material

[0047]22 pinch tunnel 62 directionally molded elastic

[0048]24 friction surface 70 piston cylinder

[0049]26 roller 72 piston rod

[0050]27 pocket 74 piston

[0051]28 clutch plate 76 valve aperture

[0052]30 engagement spring 78 flap valve

[0053]42 claw clutch 80 variable diameter valve

[0054]44 claw clutch slide 90 rolling ramp clutch plate

[0055]46 directional molded fingers 92 rolling ramp clutch slide

[0056]48 molded fingers

[0057]100 binding platform 104 nested ramp

[0058]102 ski boot 106 adjustment screw

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0059] A typical embodiment of the present invention is depicted in FIG.1A (side view). A flexible sliding board or ski 10 is shown with typicaltoe 12 and heel 14 bindings mounted. The embodiment of the inventionconsists of a force transmission rod or blade 20 secured to the ski atone end by screws, adhesives or a binding piece. The force transmissionblade passes through a pinch tunnel 22 or stirrup at the other end.Bending motion of the ski moves the force transmission rod back andforth through the pinch tunnel. The force transmission blade may haveinternal dampening or stiffening characteristics, or may be constructedto minimize those characteristics.

[0060] A close up view of the interior of the pinch tunnel containing atwo way directional clutch is shown in FIG. 1B (side view). A roller 26reciprocates back and forth with the force transmission blade, through anarrowed space in the pinch tunnel. When the roller is in theconstricted portion of the tunnel, pinching force on the forcetransmission blade is increased, causing increased friction between theforce transmission blade and the friction surface 24. When movement inone direction allows the roller to enter a pocket 27, pinching force andfrictional engagement of the pinch tunnel with the force transmissionrod is reduced. The engagement spring 30 will encourage the roller tore-enter the constricted portion of the pinch tunnel when the forcetransmission blade reciprocates back in the other direction.

[0061] A close of up view of the interior of the pinch tunnel containinga single directional clutch is shown in FIG. 1C (side view). When theforce transmission rod operates in the direction of engagement, the clawclutch slide 44 moves up the ramps of the claw clutch to a position thatincreases the pinching force on the force transmission blade. The bladecan then continue to move in that direction with the maximum frictionforce that can be applied by the pinch tunnel. When the forcetransmission blade reciprocates back forward the claw clutch sliderelaxes back down into a more open position, reducing friction in thepinch tunnel. Construction of the pinch tunnel as a bent member attachedto the ski is shown in FIG. 1D (end view) along with the forcetransmission rod and clutch.

[0062] Prior art is shown in FIGS. 2A-2C. FIG. 2A shows a forcetransmission rod that engages as the ski is bent, and a force versusdisplacement graph showing the characteristic increase in stiffness ofthis arrangement. FIG. 2B shows a force transmission rod that isreleased from a pinch tunnel as the ski is bent, and the force diagramshowing the characteristic decrease in stiffness. FIG. 2C shows a forcetransmission rod connected to a piston 74 in a piston cylinder 70attached to the ski. The piston is equipped with different sized valveapertures 76 and flap valves 78 so that resistance is greater in onedirection (rebound) than the other. The force graph shows resistance inthe bending direction determined by the stiffness of the ski, butmoderated in the return direction by the energy absorption of the pistonfluid. Damping is dependent upon rate of ski movement, so is shown asmultiple lines.

[0063] Characteristics of the embodiments of the present invention areshown in FIGS. 2D-2F. FIG. 2D shows a two direction, limited rangeclutch. The force graph shows how the engagement of the clutch stiffensthe ski at initial conditions to increase control, and also at theterminal range of motion for three different sized turns that utilizedifferent amounts of bending in the sliding board. FIG. 2E shows how asingle direction, limited engagement clutch that allows upward bending,but resists rebound with a constant frictional force. FIG. 2F shows atwo direction clutch attached to a damping member 16. The forcecharacteristic curve shows damping occurring in initial conditions andat the terminal end of bending where the ski will be bent in a steadystate during turn conditions. The damping is disengaged duringtransition movements between these two steady states to allow rapid turninitiation and completion.

[0064] The engagement operation of a two way clutch is illustrated inFIGS. 3A-3D. In FIG. 3A the ski is unbent, the clutch is engaged, andsmall reciprocal vibrations are being damped. In FIG. 3B, the ski beginsbending into a turn and the clutch roller moves into a pocket in thepinch tunnel, releasing damping engagement. In FIG. 3C, the skicontinues bending into the turn unimpeded by the force transmissionblade. In FIG. 3D, the ski begins straightening and the clutch rollerre-engages in the constrained portion of the pinch tunnel, dampingrebound at the fullest extent of the ski's bend.

[0065] Different embodiments of two way, limited range clutches areshown in FIGS. 4A-4F. FIG. 4A shows a pinch tunnel equipped with rollerengagement element as previously explained. FIG. 4B shows molded fingers48 constructed of plastic, rubber or viscoelastic material, that providemaximal engagement at the fully vertical position, but that relaxpinching within the pinch tunnel when bent over in either direction bymovement of the force transmission blade. FIG. 4C depicts an eccentric50 mounted on an axel 52 in the pinch tunnel, where maximum pinch forceis applied in the vertical position. Resilient material 54 encouragesre-engagement of the eccentric when the force transmission bladereciprocates in the other direction. FIG. 4D shows a friction collarwrapped around the force transmission blade. The friction collar appliesmaximum friction when passing through the constrained portion of thefriction tunnel, and relaxes friction when resting in a pocket at eitherend of movement. Friction between the friction collar and the forcetransmission blade is greater than friction between the collar and thepinch tunnel sides, so that the friction collar will re-enter theconstrained portion.

[0066] Another embodiment is shown in FIG. 4E, where viscoelasticmaterial 60 optionally covered with a friction material is designed todeform due to movement of the force transmission blade. When thematerial deforms by bending over in either direction, the pinchengagement force with the force transmission blade is reduced. FIG. 4Fshows a piston and cylinder with an additional variable diameter valve80 that partially engages with the damping fluid. The engagement withthe fluid causes the valve to follow the movements of the piston, andconstrain movement of the piston over a limited range by blocking avalve aperture during part of the following movement.

[0067] Different embodiments of one way clutches are shown in FIGS.5A-5D. FIG. 5A shows a directionally molded material 62 of plastic,elastic or viscoelastic material that relaxes pinch force when foldedover by movement of the force transmission blade in one direction, butincreases force by jamming in the other direction. FIG. 5B shows a clawclutch, the operation of which was explained previously. FIG. 5C shows arolling ramp clutch plate 90 and slide 92 that operates similarly to theclaw clutch, but with reduced friction. FIG. 5D shows directionallymolded fingers 46 of plastic or elastic material that fold over formovement of the force transmission rod in one direction.

[0068] Various arrangements of the present invention are show in FIGS.6A-6E. In FIG. 6A a stiffening 18 or damping member is attached to theremote end of the force transmission rod. In FIG. 6B the clutch isintegrated with a stiffening or dampening member at the local end of theforce transmission rod. In FIG. 6C an dampening member is integrated aspart of the pinch tunnel. In FIGS. 6D and 6E the clutch mechanism,damping element and force transmission element are integrated with thebinding platform 100, mounting plate or binding mechanism.

[0069] Possibilities for changing the range of engagement of clutchesand amount of pinch force and friction are shown in FIGS. 7A-C. In FIG.7A, a mechanism of nested ramp 104 elements is shown that allows foradjustment of the range where pinch force is applied in a pinch tunnel.FIG. 7B depicts use of an adjustment screw 106 to provide a variablestop for constraining the maximum engagement force of a claw clutch.FIG. 7C shows an adjustment screw used to increase or decrease thepinching force between a friction material and the force transmissionblade.

Summary Ramifications and Scope

[0070] Accordingly, significant improvements in sliding boardperformance can result from use of the invention. The invention willallow use of stronger damping forces during turning and straight runningconditions without impeding the dynamic transitions of the slidingboard. The invention allows damping or biasing forces to be appliedduring turns of different sizes that correspond to different degrees ofbending in the ski. The engagement of damping can be applied independentof terrain conditions or skier weight distribution. The damping orbiasing can be directionally applied without the requirement for a heavyand expensive hydraulic cylinder. The increased range of damping andstiffening strategies provided by the invention can be applied todifferent portions of the ski to maximize the skier's ability to utilizeenergy stored in the bend of the ski.

[0071] Although the descriptions above contain many specificities, theseshould not be construed as limiting the scope of the invention, butmerely as providing illustrations of the some of the presently preferredembodiments of the invention. For example, the sliding board could be aski, snowboard, monoski, toboggan, etc. The placement of forcetransmission, clutch and damping or stiffening elements can bere-arranged into many visually different but operationally similarconfigurations.

[0072] Thus the scope of the invention should be determined by theappended claims and their legal equivalents, rather than by the examplesgiven.

What is claimed is:
 1. An apparatus for dampening or stiffening a sliding board comprising: a) a sliding board, b) a force transmission element attached to said sliding board for transmitting energy from the bend or twist in sliding board, c) a clutching means for selectively engaging and disengaging force transmission element to the sliding board in both directions of movement over a limited range.
 2. The clutching means of claim 1 wherein the clutching means is constructed with a rolling, bending or deforming member that can apply variable pinching force to said force transmission element.
 3. The clutching means of claim 1 wherein the clutching means is constructed with a rolling member, and the range of engagement of said rolling member can be varied by lengthening or contracting the engaged range of movement over of which said rolling member moves.
 4. The clutching means of claim 1 wherein the clutching means is constructed of a hydraulic cylinder, piston and valves, where one or more valves operates only over a limited range of motion, in order to constrain the motion of said piston in said cylinder only over a portion of the total movement of said piston in said cylinder.
 5. The force transmission element of claim 1 constructed with a degree of flexibility or energy loss when flexed so as to apply an innate biasing or damping characteristic to said sliding board.
 6. The force transmission element of claim 1 further including a dampening device for absorbing vibration energy of said sliding board.
 7. The force transmission element of claim 1 further including a stiffening device for increasing stiffening bias of said sliding board.
 8. The force transmission element of claim 1 wherein the force transmission member is integrated with the binding mounts, binding platform, binding mechanism or ski boot and binding combination of said sliding board.
 9. The clutching means of claim 1 wherein the clutching means is attached directly to a dampening or stiffening member.
 10. An apparatus for dampening or stiffening a sliding board comprising: a) a sliding board, b) a force transmission element attached to said sliding board for transmitting energy from the bend or twist in sliding board, c) a clutching means for frictionally engaging the force transmission element to the sliding board in a single direction of bend.
 11. The clutching means of claim 10 wherein the clutching means is constructed with a rolling, bending or deforming member that can apply variable pinching force to said force transmission element.
 12. The force transmission element of claim 10 constructed with a degree of flexibility or energy loss when flexed so as to apply an innate biasing or damping characteristic to said sliding board.
 13. The force transmission element of claim 10 further including a dampening device for absorbing vibration energy of said sliding board.
 14. The force transmission element of claim 10 further including a stiffening device for increasing stiffening bias of said sliding board.
 15. The force transmission element of claim 10 wherein the force transmission member is integrated with the binding mounts, binding platform, binding mechanism or ski boot and binding combination of said sliding board.
 16. The clutching means of claim 10 wherein the clutching means is attached directly to a dampening or stiffening member.
 17. One or more instances of the apparatus of claim 1 or 10 applied to a sliding board wherein the instances are applied to multiple locations or sections of said sliding board, so as to act upon each section of said sliding board.
 18. One or more instances of the apparatus of claim 1 or 10 applied to a sliding board wherein the instances are applied in a transverse or diagonal manner with respect to length of said sliding board, in order to change the torsional bending or vibration characteristics of said sliding board.
 19. One or more instances of the apparatus of claim 1 or 10 applied to a sliding board wherein the instances are constructed with damping or stiffening means having different characteristics so as to asymmetrically affect the stiffness of the sliding board longitudinally or torsionally. 